Windshields of vehicles are typically cleaned using a wiper assembly mounted to a driven wiper arm or driving arm which is mounted for oscillating pivotal movement to effect a back-and-forth wiping motion of the wiper assembly across the windshield. The wiper assembly typically includes a blade arm or blade arm assembly to which a rubber wiper blade is secured. Wiper blades made of rubber have proven to be especially well suited for cleaning unwanted water from a windshield.
One of the problems with known wiper assemblies is that the rubber wiper blade typically included in the assembly is poorly suited for certain windshield cleaning jobs. For example, a rubber wiper blade is not as effective as a hard scraper for removing frost or ice from a windshield. Also, a rubber wiper blade often will not effectively remove insects, dirt or other debris from the windshield. While it might be possible to temporarily replace the rubber wiper blade with a wiper blade of a material more suited to the particular cleaning task at hand, such is not a practical solution since the primary and usual purpose of windshield wipers is to squeegee off excess water for clearer vision. Other more abrasive materials will not work as well for this purpose. This shortcoming is aggravated by the relative inconvenience of changing wiper blades to suit the particular cleaning task at hand, particularly when the vehicle is in operation.
U.S. patent Ser. No. 4,745,653 of Bliznak discloses a wiper/scraper/washer blade for windshields in which a multiple edged wiper blade is rotably mounted to a blade arm so that one can manually rotate the wiper blade and select the type of blade edge appropriate for the particular cleaning task at hand. For example, Bliznak discloses a hard-pointed edge for cutting through ice and softer edges for acting as a squeegee. One drawback to the wiper/scraper/washer blade of Bliznak is that to change blade edges, one would typically stop operation of the windshield wipers and manually rotate the blade. Obviously, this can be impractical or inconvenient in adverse weather conditions or while the vehicle is moving.